The most commonly used process for industrial manufacturing of alcohol at distilleries comprises the following general steps:
Admission and treatment (clearing, water dilution and sulphuric acid addition) of molasses from sugar cane processing plants. PA0 A fermenting step wherein the yeast is added to the diluted solution in order to ferment the sugars, as well as sulphuric acid to lower the pH of the diluted solution to about 3.7-4.5. PA0 Water, PA0 Wornactive-out yeast remainders, PA0 Non-fermented products, PA0 Other organic products, ketones, medium or high molecular weight unmatched alcohols, which were eliminated during production due to toxicity. PA0 Sulphates and other sulphur compounds from the sulphuric acid reaction that were added for product clearing and pH control. PA0 Various cations either from the original plant or added as a part of the distillation process such as K,Na,Mg,Ca,Fe, etc. PA0 1) to eliminate contaminant products; PA0 2) to extract from them useful products which, are to be utilized in different industrial processes and which can also be marketed or re-used. PA0 A large volume of water to be re-used at the distillery; PA0 Products designed for industrial application derived from the different polymers utilizing their water-reducer or fluidizer, tensio-active, dispersant, adhesive and binding features. PA0 82% industrial water; PA0 14% dispersant, tenso-active, adhesive and industrial agglutinant agents, as an active component; PA0 4% precipitates. PA0 Many basic operations (milling, heating and separation) need to be carry out before attaining the lye containing dispersants, tensio-actives and agglutinants, which not only increases the cost of the whole process but also determines a performance reduction due to the numerous steps to be carried out. PA0 The lack of homogeneousness of dispersants, tensio-actives and agglutinants depends on the nature of the wood type, which at times may be very heterogeneous and creates serious problems in formulation adjustments. PA0 Clearing by way of disc type centrifuge machines, when the effluent has a concentration of between 32% and 45%, that is, between the first and second clearing steps. Thus, 0.1% of insoluble matter is obtained at the centrifuge machine outlet. PA0 Clearing the effluent after concentrating and when this effluent has a concentration of between 45% and 52%, and using gravity-tanks. For settling, these tanks are constructed with a tapered bottom as well as with sample takers at several heights in order to continuously check the insoluble matter concentration and the settling state. Using this type of clearing it is possible to obtain a percentage of insoluble matter less than 1.5 according to settling time. This clearing method requires many tanks of great volumes and consequently it is not recommended. PA0 Carrying out clearing by using (both of the above-described methods) in the same process. PA0 it is based on a by-product, which has not been used so far, and it represents a serious environmental threat; PA0 it is a very simple process which requires few steps and which consequently reduces cost and increases performance of the whole process; PA0 it is a modular process which makes it possible to obtain polymeric complex either in an aqueous solution at the desired concentration and with a degree of insoluble matter allowed according to application or in powder form, which facilitates and cuts costs of transport and storage; PA0 the water reducers, fluidizers, dispersants, tensio-actives and agglutinants (solution or powder) obtained according to the process of the invention show a high homogeneity due to the fact that the raw material is always the same or very similar which facilitates industrial usage since it makes it easier to prepare formulations as required.
Fermentation produces alcohols, particularly ethanol and non-fermented products.
In alcohol distillation, approximately a 12 liters of residue per liter of alcohol is produced. A medium-sized distillery produces 50,000 liters of alcohol a day which is equivalent to 600,000 liters of residual effluents. This residue is highly pollutant due to its high oxygen chemical requirements (OCR) and oxygen biological requirements (OBR).
Its qualitative composition is as follows:
Products joined to the sugar or starch from the beginning of the process, as liquid compounds in the primary product (molasses or beetroot, barley, potato honeys etc.) in the form of non fermentable juices (sugars) which are incorporated into the main raw material in order to separate them later from the alcohols obtained.
These effluents ferment almost spontaneously and produce very unpleasant sulphurous odors and due to their OCR and OBR are highly pollutant in their capacity for taking oxygen from the environment, affecting flora and fauna. A medium-sized distillery as aforementioned, which produces 50,000 liters of alcohol a day has a contamination level equal to a city of 500,000 inhabitants.
At certain sites, where the distillery is located near plantations, residuals are used to irrigate these plantations.
Nevertheless, this use is not considered appropriate due to the disagreeable odor which, they emit and high transport costs. The most common method for eliminating these residuals consists of uncontrolled disposal into rivers, seas and swamps causing severe environmental damage.